London -LRB- CNN -RRB- -- At least seven people are confirmed dead and 51 injured in a `` horrific '' traffic accident in southwest England , Somerset police said Saturday .

The accident involved 34 vehicles , including cars , vans and large trucks , police said , some of which erupted into a `` fireball . ''

Assistant Chief Constable Anthony Bangham told reporters more bodies are feared to be still trapped in badly burnt vehicles .

Some of the vehicles are `` burnt to the ground '' and unrecognizable , he said in a televised news conference after visiting the site . `` This is a horrific scene . ''

The crash occurred about 8:25 p.m. Friday on the M5 highway near Taunton in Somerset , about 70 kilometers -LRB- 45 miles -RRB- southwest of Bristol , according to the Devon and Somerset Fire Rescue .

Bangham said poor weather was likely to have been a factor , with wet roads after rain and banks of fog reported in the area .

Police were also looking into a nearby fireworks display to see if it may have played a role , he said .

He praised members of the public who showed `` real bravery '' in trying to rescue people from blazing vehicles , as well as the efforts of the emergency services .

`` For a motorway incident , this is just about as big as it gets , '' he said . `` This is a highly complex , very dramatic incident for our officers . ''

He said part of the highway would remain closed in both directions until at least Sunday .

About 15 fire trucks were sent to the scene , as rescue workers battled to extinguish blazing vehicles and cut free trapped passengers .

Avon and Somerset Police have appealed for anyone who witnessed the events to get in touch , especially if they have mobile phone footage .

CNN 's Nicky Robertson contributed to this report .

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NEW : At least seven people are confirmed dead and 51 injured

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NEW : More people are feared trapped in vehicles , police say

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NEW : Poor weather and a nearby fireworks display may have been a factor

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NEW : The crash in Somerset involved 34 vehicles , including heavy trucks